Poster session what?
One of the stranger features of national science meetings is the poster session. At the Geological Society of America Annual Meeting in Charlotte this year (or any other) you have a choice of giving a talk or a poster session. A poster session means that you present data and interpretations within a 4 foot by 8 foot poster, and stand there from 2-4 p.m. and 4:30-6 p.m. to discuss it with whoever is interested.
A poster session often presents works in progress. The valuable part is that you get a lot of feedback and discussion. The downside is that you have to stand on a very hard floor for a few hours. If you are giving a talk, you may have 3 minutes for discussion or questions. If you are giving a poster session, there’s a lot more time for talk. In a place like GSA, a lot of different specialties are represented, so you get a wide variety of feedback.
The first picture is the poster session area at Charlotte GSA this year. Both sides of the boards hold posters. It looks like a lot of space, but the area for poster sessions at the American Geophysical Union are much larger, like the size of a football field.
Trish was presenting results from her analysis of giant squids. In an earlier paper, Trish and I (and a cast of thousands) found organic material consistent with chitin preserved in an Eocene age cephalopod. Now Trish (and I) are looking at the hard parts of the giant squid. Somewhere along the evolutionary line, cephalopods internalized their shells. Were the shells made of calcite, aragonite, a bone-like apatite mineral, or chitin? To figure that out, you must first figure out what happened to the hard parts after burial.
Bailey Mueller worked as my intern this summer, on my long-running pyrite disease project. Pyrite picks up water and oxygen, leading to the formation of sulfate minerals, eventually leading to the formation of sulfuric acid. The sulfuric acid is strong enough to eat a hole in nearly anything. When a fossil has “pyrite disease” it will eventually be destroyed by acid. Worse, one this sort of pyrite decomposition shows up in a storage case, it appears to spread throughout the case. Some researchers have speculated that it was actually spread by bacteria, hence the name “pyrite disease.”
To test that hypothesis, I dried out a mixture of clay, sulfate minerals and quartz in a vacuum oven, and put it on a polished piece of pyrite to see what would happen. Another piece of pyrite without the seeding mixture was kept next to it. I used a sealed container where I could control humidity.
Bailey did the petrography and the descriptions of the samples as part of her internship. Then she used reflectance infrared spectroscopy to identify the remaining minerals that grew. What she found was that the mixture of dried materials would enhance oxidation at the new site. Bacteria weren’t required. Even at 56% relative humidity, new stuff was growing.
Humidity cycles during the year, even with climate control. During dry cycles, sulfate minerals dry to a fine powder that can blow through a case. They can also be spread by hand. Once the humidity rises, they will happily start growing all over again. Our Collections house high-value items in both Paleo and Geology, and this is important information for our job of caring for these specimens “in perpetuity.”
Back to the posters: Rather than torture Bailey by making her give a talk to a bunch of Ph.D.’s, I suggested she present her results as a poster session. I am proud to report that she did an excellent job of answering questions and defending her work. I think she came through her first professional meeting with flying colors.